DOC: add double backticks for sphinx compatibility

Co-authored-by: rhshadrach <[email protected]>

Author: tuhinsharma121

pandas/core/groupby/generic.py

@@ -2695,7 +2695,7 @@ def hist(
         Returns
         -------
         matplotlib.Axes or numpy.ndarray
-            A `matplotlib.Axes` object or an array of `Axes` objects, depending on
+            A ``matplotlib.Axes`` object or an array of ``Axes`` objects, depending on
             the layout and grouping.
 
         See Also